List organisations on sub-sector pages

  As a user
  I want to see the organisations associated with the content in the
  specialist subsector I am browsing
  So that I can browse to the organisations to find out more information

Story: https://www.pivotaltracker.com/story/show/75807888
Style the organisations on specialist sector pages

Mostly, this is copied from specialist-frontend with a few tweaks to
spacing and padding.